I am running Aperture 3 (in 32-bit mode, as I wanted to use some existing plugins) and I am finding it increasingly sluggish in doing most anything. (I switched from iPhoto to Aperture about 3 months ago, so I'm still in the learning curve).

For instance, when viewing pictures (fullscreen) within a project, the "loading..." notice persists for several seconds and there's about a 5 second delay between pushing the right arrow and the next photo loading (and the spinning beach ball appears with some regularity as well).

This is most likely a harddrive issue, switching to an SSD should make quite an improvement. It could also be the processor (it most likely has to render the file from raw), but your current setup should be sufficient for half a year or so.

_________________I take pictures so quickly, my highschool was "Continuous High".